Vehicle having suspension with continuous damping control

ABSTRACT

A damping control system for a vehicle having a suspension located between a plurality of ground engaging members and a vehicle frame includes at least one adjustable shock absorber having an adjustable damping characteristic. The system also includes a controller coupled to each adjustable shock absorber to adjust the damping characteristic of each adjustable shock absorber, and a user interface coupled to the controller and accessible to a driver of the vehicle. The user interface includes at least one user input to permit manual adjustment of the damping characteristic of the at least one adjustable shock absorber during operation of the vehicle. Vehicle sensors are also be coupled to the controller to adjust the damping characteristic of the at least one adjustable shock absorber based vehicle conditions determined by sensor output signals.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 15/377,640, filed Dec. 13, 2016, which is a continuation of U.S.application Ser. No. 14/935,184, filed Nov. 6, 2015, which is acontinuation of U.S. application Ser. No. 14/507,355, filed Oct. 6,2014, which is a continuation-in-part of U.S. application Ser. No.14/074,340, filed on Nov. 7, 2013, which claims the benefit of U.S.Application Ser. No. 61/723,623, filed on Nov. 7, 2012, the disclosuresof which are expressly incorporated herein by reference.

BACKGROUND AND SUMMARY OF THE DISCLOSURE

The present disclosure relates to improved suspension for a vehiclehaving continuous “on-the-go” damping control for shock absorbers.

Currently some off-road vehicles include adjustable shock absorbers.These adjustments include spring preload, high and low speed compressiondamping and/or rebound damping. In order to make these adjustments, thevehicle is stopped and the operator makes an adjustment at each shockabsorber location on the vehicle. A tool is often required for theadjustment. Some on-road automobiles also include adjustable electricshocks along with sensors for active ride control systems. However,these systems are normally controlled by a computer and are focused onvehicle stability instead of ride comfort. The system of the presentdisclosure allows an operator to make real time “on-the-go” adjustmentsto the shocks to obtain the most comfortable ride for given terrain andpayload scenarios.

Vehicles often have springs (coil, leaf, or air) at each wheel, track,or ski to support a majority of the load. The vehicle of the presentdisclosure also has electronic shocks controlling the dynamic movementof each wheel, ski, or track. The electronic shocks have a valve thatcontrols the damping force of each shock. This valve may controlcompression damping only, rebound damping only, or a combination ofcompression and rebound damping. The valve is connected to a controllerhaving a user interface that is within the driver's reach for adjustmentwhile operating the vehicle. In one embodiment, the controller increasesor decreases the damping of the shock absorbers based on user inputsreceived from an operator. In another embodiment, the controller hasseveral preset damping modes for selection by the operator. Thecontroller is also coupled to sensors on the suspension and chassis toprovide an actively controlled damping system.

In an illustrated embodiment of the present disclosure, a dampingcontrol method is provided for a vehicle having a suspension locatedbetween a plurality of wheels and a vehicle frame, a controller, aplurality of vehicle condition sensors, and a user interface, thesuspension including a plurality of adjustable shock absorbers includinga front right shock absorber, a front left shock absorber, a rear rightshock absorber, and a rear left shock absorber. The damping controlmethod includes receiving with the controller a user input from the userinterface to provide a user selected mode of damping operation for theplurality of adjustable shock absorbers during operation of the vehicle;receiving with the controller a plurality of inputs from the pluralityof vehicle condition sensors including a brake sensor, a throttlesensor, and a vehicle speed sensor; determining with the controllerwhether vehicle brakes are actuated based on an input from the brakesensor; determining with the controller a throttle position based on aninput from the throttle sensor; and determining with the controller aspeed of the vehicle based on an input from the vehicle speed sensor.The illustrative damping control method also includes operating thedamping control in a brake condition if the brakes are actuated, whereinin the brake condition the controller adjusts damping characteristics ofthe plurality of adjustable shock absorbers based on condition modifiersincluding the user selected mode and the vehicle speed; operating thedamping control in a ride condition if the brakes are not actuated and athrottle position is less than a threshold Y, wherein in the ridecondition the controller adjusts damping characteristics of theplurality of adjustable shock absorbers based on condition modifiersincluding the user selected mode and the vehicle speed; operating thedamping control in the ride condition if the brakes are not actuated,the throttle position in greater than the threshold Y, and the vehiclespeed is greater than a threshold value Z; and operating the dampingcontrol in a squat condition if the brakes are not actuated, thethrottle position in greater than the threshold Y, and the vehicle speedis less than the threshold value Z, wherein in the squat condition thecontroller adjusts damping characteristics of the plurality ofadjustable shock absorbers based on condition modifiers including theuser selected mode, the vehicle speed, and a throttle percentage.

Additional features of the present disclosure will become apparent tothose skilled in the art upon consideration of the following detaileddescription of illustrative embodiments exemplifying the best mode ofcarrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many additional features of the present systemand method will become more readily appreciated and become betterunderstood by reference to the following detailed description when takenin conjunction with the accompanying drawings.

FIG. 1 is a block diagram illustrating components of a vehicle of thepresent disclosure having a suspension with a plurality of continuousdamping control shock absorbers and a plurality of sensors integratedwith the continuous damping controller;

FIG. 2 illustrates an exemplary user interface for controlling dampingat a front axle and a rear axle of the vehicle;

FIG. 3 illustrates another exemplary embodiment of a user interface forcontinuous damping control of shock absorbers of the vehicle;

FIG. 4 illustrates yet another user interface for setting various modesof operation of the continuous damping control depending upon theterrain being traversed by the vehicle;

FIG. 5 illustrates an adjustable damping shock absorber coupled to avehicle suspension;

FIG. 6 is a flow chart illustrating vehicle platform logic forcontrolling various vehicle parameters in a plurality of different userselectable modes of operation;

FIG. 7 is a block diagram illustrating a plurality of differentcondition modifiers used as inputs in different control modes to modifydamping characteristics of electronically adjustable shock absorbers ordampers in accordance with the present disclosure;

FIG. 8 is a flow chart illustrating a damping control method forcontrolling the vehicle operating under a plurality of vehicleconditions based upon a plurality of sensor inputs in accordance withone embodiment of the present invention;

FIG. 9 is a flow chart illustrating another embodiment of a dampingcontrol method of the present disclosure;

FIG. 10 is a flow chart illustrating yet another damping control methodof the present disclosure;

FIG. 11 is a sectional view of a stabilizer bar of the presentdisclosure which is selectively decoupled under certain vehicleconditions;

FIG. 12 illustrates the stabilizer bar of FIG. 11 with an actuator in alocked position to prevent movement of a piston of the stabilizer bar;

FIG. 13 is a sectional view similar to FIG. 12 illustrating an actuatorin an unlocked position disengaged from the piston of the stabilizer barto permit movement of the piston relative to a cylinder; and

FIG. 14 illustrates an x-axis, a y-axis, and a z-axis for a vehicle suchas an ATV.

Corresponding reference characters indicate corresponding partsthroughout the several views. Although the drawings representembodiments of various features and components according to the presentdisclosure, the drawings are not necessarily to scale and certainfeatures may be exaggerated in order to better illustrate and explainthe present disclosure.

DETAILED DESCRIPTION OF THE DRAWINGS

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference will now be made to the embodimentsillustrated in the drawings, which are described below. The embodimentsdisclosed below are not intended to be exhaustive or limit the inventionto the precise form disclosed in the following detailed description.Rather, the embodiments are chosen and described so that others skilledin the art may utilize their teachings. It is understood that nolimitation of the scope of the invention is thereby intended. Theinvention includes any alterations and further modifications in theillustrated devices and described methods and further applications ofthe principles of the invention which would normally occur to oneskilled in the art to which the invention relates.

Referring now to FIG. 1, the present disclosure relates to a vehicle 10having a suspension located between a plurality of ground engagingmembers 12 and a vehicle frame 14. The ground engaging members 12include wheels, skis, guide tracks, treads or the like. The suspensiontypically includes springs 16 and shock absorbers 18 coupled between theground engaging members 12 and the frame 14. The springs 16 may include,for example, coil springs, leaf springs, air springs or other gassprings. The air or gas springs 16 may be adjustable. See, for example,U.S. Pat. No. 7,950,486 incorporated herein by reference. The springs 16are often coupled between the vehicle frame 14 and the ground engagingmembers 12 through an A-arm linkage 70 (See FIG. 5) or other typelinkage. Adjustable shock absorbers 18 are also coupled between theground engaging members 12 and the vehicle frame 14. An illustratingembodiment, a spring 16 and shock 18 are located adjacent each of theground engaging members 12. In an ATV, for example, four springs 16 andadjustable shocks 18 are provided adjacent each wheel 12. Somemanufacturers offer adjustable springs 16 in the form of either airsprings or hydraulic preload rings. These adjustable springs 16 allowthe operator to adjust the ride height on the go. However, a majority ofride comfort comes from the damping provided by shock absorbers 18.

In an illustrated embodiment, the adjustable shocks 18 are electricallycontrolled shocks for adjusting damping characteristics of the shocks18. A controller 20 provides signals to adjust damping of the shocks 18in a continuous or dynamic manner. The adjustable shocks 18 may beadjusted to provide differing compression damping, rebound damping orboth.

In an illustrated embodiment of the present disclosure, a user interface22 is provided in a location easily accessible to the driver operatingthe vehicle. Preferably, the user interface 22 is either a separate userinterface mounted adjacent the driver's seat on the dashboard orintegrated onto a display within the vehicle. User interface 22 includesuser inputs to allow the driver or a passenger to manually adjust shockabsorber 18 damping during operation of the vehicle based on roadconditions that are encountered. In another illustrated embodiment, theuser inputs are on a steering wheel, handle bar, or other steeringcontrol of the vehicle to facilitate actuation of the dampingadjustment. A display 24 is also provided on or next to the userinterface 22 or integrated into a dashboard display of the vehicle todisplay information related to the shock absorber damping settings.

In an illustrated embodiment, the adjustable shock absorbers 18 aremodel number CDC (continuous damping control) electronically controlledshock absorbers available from ZF Sachs Automotive. See Causemann,Peter; Automotive Shock Absorbers: Features, Designs, Applications, ISBN3-478-93230-0, Verl. Moderne Industrie, Second Edition, 2001, pages53-63, incorporated by reference herein for a description of the basicoperation of the shock absorbers 18 in the illustrated embodiment. It isunderstood that this description is not limiting and there are othersuitable types of shock absorbers available from other manufacturers.

The controller 20 receives user inputs from the user interface 22 andadjusts the damping characteristics of the adjustable shocks 18accordingly. As discussed below, the user can independently adjust frontand rear shock absorbers 18 to adjust the ride characteristics of thevehicle. In certain other embodiments, each of the shocks 18 isindependently adjustable so that the damping characteristics of theshocks 18 are changed from one side of the vehicle to another.Side-to-Side adjustment is desirable during sharp turns or othermaneuvers in which different damping characteristics for shock absorbers18 on opposite sides of the vehicle improves the ride. The dampingresponse of the shock absorbers 18 can be changed in a matter ofmicroseconds to provide nearly instantaneous changes in damping forpotholes, dips in the road, or other driving conditions.

A plurality of sensors are also coupled to the controller 20. Forexample, the global change accelerometer 25 is coupled adjacent eachground engaging member 12. The accelerometer provides an output signalcoupled to controller 20. The accelerometers 25 provide an output signalindicating movement of the ground engaging members and the suspensioncomponents 16 and 18 as the vehicle traverses different terrain.

Additional sensors may include a vehicle speed sensor 26, a steeringsensor 28 and a chassis accelerometer 30 all having output signalscoupled to the controller 20. Accelerometer 30 is illustratably athree-axis accelerometer located on the chassis to provide an indicatingof forces on the vehicle during operation. Additional sensors include abrake sensor 32, a throttle position sensor 34, a wheel speed sensor 36,and a gear selection sensor 38. Each of these sensors has an outputsignal coupled to the controller 20.

In an illustrated embodiment of the present disclosure, the userinterface 22 shown in FIG. 2 includes manual user inputs 40 and 42 foradjusting damping of the front and rear axle shock absorbers 18. Userinterface 22 also includes first and second displays 44 and 46 fordisplaying the damping level settings of the front shock absorbers andrear shock absorbers, respectively. In operation, the driver orpassenger of the vehicle can adjust user inputs 40 and 42 to providemore or less damping to the shock absorbers 18 adjacent the front axleand rear axle of the vehicle. In the illustrated embodiment, user inputs40 and 42 are rotatable knobs. By rotating knob 40 in a counterclockwise direction, the operator reduces damping of the shock absorbers18 adjacent the front axle of the vehicle. This provides a softer ridefor the front axle. By rotating the knob 40 in a clockwise direction,the operator provides more damping on the shock absorbers 18 adjacentthe front axle to provide a stiffer ride. The damping level for frontaxle is displayed in display 44. The damping level may be indicated byany desired numeric range, such as for example, between 0-10, with 10being the most stiff and 0 the most soft.

The operator rotates knob 42 in a counter clockwise direction to reducedamping of the shock absorbers 18 adjacent the rear axle. The operatorrotates the knob 42 in a clockwise direction to provide more damping tothe shock absorbers 18 adjacent the rear axle of the vehicle. Thedamping level setting of the rear shock absorbers 18 is displayed indisplay window 46.

Another embodiment of the user interface 22 is illustrated in FIG. 3. Inthis embodiment, push buttons 50 and 52 are provided for adjusting thedamping level of shock absorbers 18 located adjacent the front axle andpush buttons 54 and 56 are provided for adjusting the damping of shockabsorbers 18 located adjacent rear axle. By pressing button 50, theoperator increases the damping of shock absorbers 18 located adjacentthe front axle and pressing button 52 reducing the damping of shockabsorbers 18 located adjacent front axle. The damping level of shockabsorbers 18 adjacent front axle is displayed within display window 57.As discussed above, the input control switches can be located anydesired location on the vehicle. For example, in other illustratedembodiments, the user inputs are on a steering wheel, handle bar, orother steering control of the vehicle to facilitate actuation of thedamping adjustment.

Similarly, the operator presses button 54 to increase damping of theshock absorbers located adjacent the rear axle. The operator pressesbutton 56 to decrease damping of the shock absorbers located adjacentthe rear axle. Display window 58 provides a visual indication of thedamping level of shock absorbers 18 adjacent the rear axle. In otherembodiments, different user inputs such as touch screen controls, slidecontrols, or other inputs may be used to adjust the damping level ofshock absorbers 18 adjacent the front and rear axles. In otherembodiments, different user inputs such as touch screen controls, slidecontrols, or other inputs may be used to adjust the damping level ofshock absorbers 18 adjacent all four wheels at once.

FIG. 4 illustrates yet another embodiment of the present disclosure inwhich the user interface 22 includes a rotatable knob 60 having aselection indicator 62. Knob 60 is rotatable as illustrated bydouble-headed arrow 64 to align the indicator 62 with a particulardriving condition mode. In the illustrated embodiment, five modes aredisclosed including a smooth road mode, a rough trail mode, a rock crawlmode, a chatter mode, and a whoops/jumps mode. Depending on the drivingconditions, the operating rotates the control knob 60 to select theparticular driving mode. Controller 20 automatically adjusts dampinglevels of adjustable shocks 18 adjacent front and rear axles of thevehicle based on the particular mode selected.

It is understood that various other modes may be provided including asport mode, trail mode, or other desired mode. In addition, differentmodes may be provided for operation in two-wheel drive, four-wheeldrive, high and low settings for the vehicle. Illustrative operationmodes include:

-   -   Smooth Road Mode—Very stiff settings designed to minimize        transient vehicle pitch and roll through hard acceleration,        braking, and cornering.    -   Normal Trail Mode—Similar to smooth road mode, but a little bit        softer set-up to allow for absorption of rocks, roots, and        potholes but still have good cornering, accelerating, and        braking performance.    -   Rock Crawl Mode—This would be the softest setting allowing for        maximum wheel articulation for slower speed operation. In one        embodiment, the rock crawl mode is linked to vehicle speed        sensor 26.    -   High Speed Harsh Trail (Chatter)—This setting is between Normal        Trail Mode and Rock Crawl Mode allowing for high speed control        but very plush ride (bottom out easier).    -   Whoops and Jumps Mode—This mode provides stiffer compression in        the dampers but less rebound to keep the tires on the ground as        much as possible.    -   These modes are only examples one skilled in the art would        understand there could be many more modes depending on the        desired/intended use of the vehicle.

In addition to the driving modes, the damping control may be adjustedbased on outputs from the plurality of sensors coupled with thecontroller 20. For instance, the setting of adjustable shock absorbers18 may be adjusted based on vehicle speed from speed sensor 26 oroutputs from the accelerometers 25 and 30. In vehicles moving slowly,the damping of adjustable shock absorbers 18 is reduced to provide asofter mode for a better ride. As vehicle's speed increases, the shockabsorbers 18 are adjusted to a stiffer damping setting. The damping ofshock absorbers 18 may also be coupled and controlled by an output froma steering sensor 28. For instance, if the vehicle makes a sharp turn,damping of shock absorbers 18 on the appropriate side of the vehicle maybe adjusted instantaneously to improve ride.

The continuous damping control of the present disclosure may be combinedwith adjustable springs 16. The springs 16 may be a preload adjustmentor a continuous dynamic adjustment based on signals from the controller20.

An output from brake sensor 32 may also be monitored and used bycontroller 20 to adjust the adjustable shocks 18. For instance, duringheavy braking, damping levels of the adjustable shocks 18 adjacent thefront axle may be adjusted to reduce “dive” of the vehicle. In anillustrated embodiment, dampers are adjusted to minimize pitch bydetermining which direction the vehicle is traveling, by sensing aninput from the gear selection sensor 38 and then adjusting the dampingwhen the brakes are applied as detected by the brake sensor 32. In anillustrative example, for improved braking feel, the system increasesthe compression damping for shock absorbers 18 in the front of thevehicle and adds rebound damping for shock absorbers 18 in the rear ofthe vehicle for a forward traveling vehicle.

In another embodiment, an output from the throttle position sensor isused by controller 20 to adjust the adjustable shock absorbers 18 toadjust or control vehicle squat which occurs when the rear of thevehicle drops or squats during acceleration. For example, controller 20may stiffen the damping of shock absorbers 18 adjacent rear axle duringrapid acceleration of the vehicle. Another embodiment includesdriver-selectable modes that control a vehicle's throttle map and dampersettings simultaneously. By linking the throttle map and the CDC dampercalibrations together, both the throttle (engine) characteristics andthe suspension settings simultaneously change when a driver changesoperating modes.

In another embodiment, a position sensor is provided adjacent theadjustable shock absorbers 18. The controller 20 uses these positionsensors to stiffen the damping of the adjustable shocks 18 near the endsof travel of the adjustable shocks. This provides progressive dampingcontrol for the shock absorbers. In one illustrated embodiment, theadjustable shock position sensor is an angle sensor located on an A-armof the vehicle suspension. In another embodiment, the adjustable shocksinclude built in position sensors to provide an indication when theshock is near the ends of its stroke.

In another illustrated embodiment, based on gear selection detected bygear selection sensor 38, the system limits the range of adjustment ofthe shock absorbers 18. For example, the damping adjustment range islarger when the gear selector is in low range compared to high range tokeep the loads in the accepted range for both the vehicle and theoperator.

FIG. 5 illustrates an adjustable shock absorber 18 mounted on an A-armlinkage 70 having a first end coupled to the vehicle frame 14 and asecond end coupled to a wheel 12. The adjustable shock absorber 18includes a first end 72 pivotably coupled to the A-arm 70 and a secondend (not shown) pivotably coupled to the frame 14. A damping controlactivator 74 is coupled to controller 20 by a wire 76.

Demonstration Mode

In an illustrated embodiment of the present disclosure, a battery 80 iscoupled to controller 20 as shown in FIG. 1. For operation in ademonstration mode in a showroom, the controller 20, user interface 22and display 24 are activated using a key in an ignition of the vehicleor a wireless key to place the vehicle in accessory mode. This permitsadjustment of the adjustable shock absorbers 18 without starting thevehicle. Therefore, the operation of the continuous damping controlfeatures of the present disclosure may be demonstrated to customers in ashow room where it is not permitted to start the vehicle due to theenclosed space. This provides an effective tool for demonstrating howquickly the continuous damping control of the present disclosure worksto adjust damping of front and rear axles of the vehicle.

As described herein, the system of the present disclosure includes fourlevels or tiers of operation. In the first tier, the adjustable shockabsorbers 18 are adjusted by manual input only using the user interface22 and described herein. In the second tier of operation, the system issemi-active and uses user inputs from the user interface 22 combinedwith vehicle sensors discussed above to control the adjustable shockabsorbers 18. In the third tier of operation, input accelerometers 25located adjacent the ground engaging members 12 and a chassisaccelerometer 30 are used along with steering sensor 28 and shockabsorber stroke position sensors to provide additional inputs forcontroller 20 to use when adjusting the adjustable shock absorbers 18.In the forth tier of operation, the controller 20 cooperates with astability control system to adjust the shock absorbers 18 to provideenhanced stability control for the vehicle 10.

In another illustrated embodiment, vehicle loading information isprovided to the controller 20 and used to adjust the adjustable shockabsorbers 18. For instance, the number of passengers may be used or theamount of cargo may be input in order to provide vehicle loadinginformation. Passenger or cargo sensors may also be provided forautomatic inputs to the controller 20. In addition, sensors on thevehicle may detect attachments on the front or rear of the vehicle thataffect handling of the vehicle. Upon sensing heavy attachments on thefront or rear of the vehicle, controller 20 adjusts the adjustable shockabsorbers 18. For example, when a heavy attachment is put on to thefront of a vehicle, the compression damping of the front shocks may beincreased to help support the additional load.

In other illustrative embodiments of the present disclosure, methods foractively controlling damping of electronically adjustable shocks usingboth user selectable modes and a plurality of sensor inputs to activelyadjust damping levels are disclosed. A central controller is used toread inputs from the plurality of vehicle sensors continuously and sendoutput signals to control damping characteristics of the electronicallyadjustable shocks. Illustrative embodiments control damping of theplurality of electronically adjustable shocks based on one or more ofthe following control strategies:

-   -   Vehicle speed based damping table    -   Roll control: Vehicle steering angle and rate of steer damping        table    -   Jump control: Detect air time and adjust damping accordingly    -   Pitch control: Brake, dive, and squat    -   Use of a lookup table or a multi-variable equation based on        sensor inputs    -   Acceleration sensing: Select damping based on frequency of        chassis acceleration    -   Load sensing: Increase damping based on vehicle/box load    -   Oversteer/understeer detection    -   Factory defaults, key-on mode selection    -   Fail safe defaults to full firm    -   Time delay that turns solenoid off after a set period of time to        conserve power at idle

In illustrative embodiments of the present disclosure, a user selectablemode provides damping control for the electronic shocks. In addition tothe methods discussed above, the present disclosure includes modesselectable by the user through a knob, touch screen, push button orother user input. Illustrative user selectable modes and correspondingsensors and controls include:

In addition to damping control, the following bullet point items canalso be adjusted in each mode:

1. Factory Default Mode

2. Soft/Comfort Mode

-   -   Vehicle speed    -   Turning    -   Air born—jumps    -   eCVT: Maintain low RPM>quiet    -   higher assist EPS calibration

3. Auto/Sport Mode

-   -   Pitch control    -   Tied to brake switch    -   Throttle (CAN) position    -   Roll control    -   Lateral acceleration    -   Steering position (EPS sensor)    -   Vehicle speed    -   “Auto” means use damping table or algorithm, which incorporates        all these inputs

4. Firm/Race Mode

-   -   eCTV: Higher engagement    -   Aggressive throttle pedal map    -   Firm (lower assist at speed) EPS calibration    -   Full firm damping

5. Rock Crawling Mode

-   -   Increase ride height—spring preload    -   Rebound increase to deal with extra preload    -   Soft stabilizer bar    -   Speed limit

6. Desert/Dunes Mode

-   -   Soft stabilizer bar    -   Speed based damping    -   Firmer damping than “Soft”

7. Trail/Cornering Mode

-   -   Lower ride height    -   Stiffer stabilizer bar    -   Increase damping    -   Firm EPS calibration

8. Work Mode (Lock-out, full firm)

-   -   eCVT: Smooth engagement    -   eCVT: Maintain low RPM>quiet, dependent on engine load    -   Load sensing damping & preload

9. Economy Mode

-   -   Lower ride height    -   Engine cal    -   eCVT cal

In illustrative embodiments of the present disclosure, sensor inputsinclude one or more of the following:

-   -   Damping mode selection    -   Vehicle speed    -   4WD mode    -   ADC mode    -   Transmission mode—CVT and other transmission types    -   EPS mode    -   Ambient temp    -   Steering angle    -   Chassis Acceleration (lateral, long, vertical)    -   Steering Wheel Acceleration    -   Gyroscope    -   GPS location    -   Shock position    -   Shock temperature    -   Box load/distribution    -   Engine sensors (rpm, temp, CAN)    -   Throttle pedal    -   Brake input/pressure    -   Passenger Sensor (weight or seatbelt)

In illustrative embodiments of the present disclosure, damping controlsystem is integrated with other vehicle systems as follow:

Vehicle Systems Integration

-   -   EPS calibration        -   Unique calibrations for each driver mode. Full assist in            work or comfort mode.    -   Automatic preload adjustment setting (electronic and/or        hydraulic control)        -   Load leveling        -   Smooth trail/on-road mode=lower, Rock crawl=higher        -   Increase rebound damping for higher preloads        -   Haul mode=increased preload in rear. Implement            mode=increased preload in front    -   Vehicle speed limits        -   Increase damping with vehicle speed for control and safety            using lookup table or using an algorithm            -   adjusts the minimum damping level in all modes beside                “Firm”            -   firm mode would be at max damping independent of vehicle                speed            -   lower ride height (preload) with vehicle speed in                certain modes    -   eCVT calibration        -   Unique calibrations for each driver mode that ties in with            electronic damping and preload. (comfort mode=low rpm, soft            damping)    -   Engine/pedal map calibration        -   Unique calibrations for each driver mode that ties in with            electronic damping and preload. (comfort mode=soft pedal            map, soft damping)    -   Steer by wire    -   Load sensing    -   Decoupled wheel speed for turning    -   4 wheel steer    -   Active Stabilizer Bar Adjustment    -   Traction Control    -   Stability Control    -   ABS    -   Active Brake Bias    -   Preload control

FIG. 6 is a flow chart illustration vehicle mode platform logic for asystem and method of the present disclosure. In the illustratedembodiment, a user selects a user mode as illustrated at block 100. Theselection may be a rotary knob, a button, a touch screen input, or otheruser input. A controller 20 uses a look up cable or algorithm todetermine preload adjustments for adjustable springs at the front right,front left, rear right and rear left of the vehicle to adjust a targetride height for the vehicle as illustrated at bock 102. Controller 20receives a ride height and/or load sensor input as illustrated at block104 so that the controller 20 adjusts the spring preload based onvehicle loads.

Controller 20 then determines whether a sway bar or stabilizer barshould be connected or disconnected as illustrated at block 106. Asdiscussed in detail below, the stabilizer bar may be connected ordisconnected depending upon the selected mode and sensor inputs.

Controller 20 also implements damping control logic as discussed belowand illustrated at block 108. Controller 20 uses a damper profile forthe front right, front left, rear right, and rear left adjustable shocksas illustrated block 110. A plurality of sensor inputs are provided tothe controller 20 as illustrated at block 112 and discussed in detailbelow to continuously control the damping characteristics of theadjustable shocks.

Controller 20 uses a stored map for calibration of an electronic powersteering (EPS) of the vehicle as illustrated at block 114. Finally, thecontroller 20 uses a map to calibrate a throttle pedal position of thevehicle as illustrated at block 116. The damping control method of thepresent discloses uses a plurality of different condition modifiers tocontrol damping characteristics of the electrically adjustable shocks.Exemplary condition modifiers include parameters set by the particularuser mode selected as illustrated at block 118, a vehicle speed asillustrated at block 120, a throttle percentage as illustrated at block122. Additional condition modifiers include a drive mode sensor such as4-wheel drive sensor as illustrated at block 124, a steering positionsensor as illustrated at block 126, and a steering rate sensor asillustrated at block 128. Drive mode sensor 124 may include lockedfront, unlocked front, locked rear, unlocked rear, or high and lowtransmission setting sensors. Condition modifiers further include anx-axis acceleration sensor as illustrated at block 130, a y-axisacceleration sensor as illustrated at block 132, and a z-axisacceleration sensor illustrated at block 134. The x-axis, y-axis, andz-axis for a vehicle such as an ATV are shown in FIG. 14. Anotherillustrative condition modifier is a yaw rate sensor as illustrated atblock 136. The various condition modifiers illustrated in FIG. 7 arelabeled 1-10 and correspond to the modifiers which influence operationof the damping control logic under the various drive conditions shown inFIGS. 8-10.

In a passive method for controlling the plurality of electronic shockabsorbers, the user selected mode discussed above sets discrete dampinglevels at all corners of the vehicle. Front and rear compression andrebound are adjusted independently based on the user selected mode ofoperation without the use of active control based on sensor inputs.

One illustrated method for active damping control of the plurality ofelectronic shock absorbers is illustrated in FIG. 8. The method of FIG.8 uses a throttle sensor 138, a vehicle speed sensor 140, and a brakeswitch or brake pressure sensor 142 as logic inputs. The controller 20determines whether the brakes are on as illustrated at block 144. If so,the controller 20 operates the damping control method in a brakecondition as illustrated at block 146. In the brake condition, frontsuspension compression (dive) is detected as a result of longitudinalacceleration from braking input. In the Brake Condition 146, thecondition modifiers include the user selected mode 118 and the vehiclespeed 120 to adjust damping control. In the vehicle conditions of FIGS.8-10, the selected user mode modifier 118 determines a particularlook-up table that defines damping characteristics for adjustable shocksat the front right, front left, rear right, and rear left of thevehicle. In brake condition 146, compression damping of the front shocksand/or rebound damping on the rear shocks is provided based on the brakesignal.

In the Brake Condition 146, the controller 20 increases damping based onincreasing vehicle speed. Further, controller 20 increases compressiondamping on front and/or rebound damping on the rear shocks based onbrake sensor signal. User mode modifiers 118 select the lookup tableand/or algorithm that defines the damping characteristics at each cornerbased on above inputs.

If the brakes are not on at block 144, controller 20 determines whetherthe throttle position is greater than a threshold Y as illustrated atblock 148. If not, controller 20 operates the vehicle in a RideCondition as illustrated at block 150. In the ride condition, thevehicle is being operated in generally a straight line where vehicleride and handling performance while steering and cornering is notdetected. In the Ride Condition 150, condition modifiers used to controldamping include user mode 118, vehicle speed 120, and a drive modesensor such as 4-wheel drive sensor 124. In the Ride Condition 150, thecontroller 20 increases damping based on the vehicle speed. User modemodifiers 118 select the lookup table and/or algorithm that defines thedamping characteristics at each corner based on above inputs.

If the throttle position in greater than the threshold Y at block 148,the controller 20 determines whether a vehicle speed is greater than athreshold value Z at block 152. If so, the controller 20 operates thevehicle in the Ride Condition at block 150 as discussed above. If thevehicle speed is less than the threshold value Z at block 152, thecontroller 20 operates the vehicle in a Squat Condition as illustratedat block 154. In the Squat Condition 154, condition modifiers forcontrolling damping include the user selected mode 118, the vehiclespeed 120, and the throttle percentage 122. During a Squat Condition154, compression damping on the rear shocks and/or rebound damping onthe front shocks is increased based upon the throttle sensor signal andvehicle speed. Rear suspension compression (squat) is a result oflongitudinal acceleration from throttle input.

In the Squat Condition 154, the controller 20 increases damping based onincreasing vehicle speed. Further, controller 20 increases compressiondamping on rear and/or rebound damping on the front shocks based on thethrottle sensor signal and vehicle speed. User mode modifiers 118 selectthe lookup table and/or algorithm that defines the dampingcharacteristics at each corner based on above inputs.

Another embodiment of the present disclosure including different sensorinput options is illustrated in FIG. 9. In the FIG. 9 embodiment, athrottle sensor 138, vehicle speed sensor 140, and brake sensor 142 areused as inputs as discussed in FIG. 8. In addition, a steering ratesensor 156 and steering position sensor 158 also provide inputs to thecontroller 20. Controller 20 determines whether an absolute value of thesteering position is greater than a threshold X or an absolute value ofthe steering rate is greater than a threshold B as illustrated at block160. If not, controller 20 determines whether the brakes are on asillustrated at block 162. If not, controller 20 determines whether thethrottle position is greater than a threshold Y as illustrated at block164. If the throttle position is greater than the threshold Y at block164, controller 20 operates the vehicle in the Ride Condition asillustrated at block 150 and discussed above. In the Ride Condition 150,the controller 20 increases damping based on the vehicle speed. Usermode modifiers 118 select the lookup table and/or algorithm that definesthe damping characteristics at each corner based on above inputs.

If the throttle position is greater than the threshold Y at block 164,controller 20 determines whether the vehicle speed is greater than athreshold Z as illustrated at block 166. If so, controller 20 operatesthe vehicle in the Ride Condition as illustrated at block 150. If thevehicle speed is less than the threshold Z at block 166, controller 20operates the vehicle in Squat Condition 154 discussed above withreference to FIG. 8. In the Squat Condition 154, the controller 20increases damping based on increasing vehicle speed. Further controller20 increases compression damping on rear and/or rebound damping on thefront shocks based on the throttle sensor signal and vehicle speed. Usermode modifiers 118 select the lookup table and/or algorithm that definesthe damping characteristics at each corner based on above inputs.

If the brakes are on at block 162, controller 20 operates the vehicle inthe Brake Condition 146 as discussed above with reference to FIG. 8. Inthe Brake Condition 146, the controller 20 increases damping based onincreasing vehicle speed. Further controller 20 increases compressiondamping on front and/or rebound damping on the rear shocks based onbrake sensor signal. User mode modifiers 118 select the lookup tableand/or algorithm that defines the damping characteristics at each cornerbased on above inputs.

If the absolute value of the steering position is greater than thethreshold X or the absolute value of the steering rate is greater thanthe threshold B at block 160, controller 20 determines whether thebrakes are on as illustrated at block 168. If so, controller 20 operatesthe vehicle in a Brake Condition as illustrated at block 170. In theBrake Condition 170, mode modifiers for controlling damping include theuser input 118, the vehicle speed 120, and the steering rate 128.

In the Brake Condition 170, the controller 20 increases damping based onincreasing vehicle speed. Further, controller 20 increases compressiondamping on the outside front corner shock based on inputs from thesteering sensor, brake sensor, and vehicle speed sensor. User modemodifiers 118 select the lookup table and/or algorithm that defines thedamping characteristics at each corner based on above inputs.

If the brakes are not on at block 168, controller 20 determines whetherthe throttle position is greater than a threshold Y as illustrated atblock 172. If not, vehicle controller 20 operates the vehicle in aRoll/Cornering Condition as illustrated at block 174. In theRoll/Cornering Condition at block 174, the condition modifiers forcontrolling damping include user mode 118, the steering position 126,and the steeling rate 128. In a Roll/Cornering Condition, vehicle bodyroll occurs as a result of lateral acceleration due to steering andcornering inputs.

In the Roll/Cornering Condition 174, the controller 20 increases dampingbased on increasing vehicle speed. Further controller 20 increasescompression damping on the outside corner shocks and/or rebound dampingon the inside corner shocks when a turn event is detected via steeringsensor. For a left hand turn, the outside shock absorbers are the frontright and rear right shock absorbers and the inside shock absorbers arefront left and rear left shock absorbers. For a right hand turn, theoutside shock absorbers are the front left and rear left shock absorbersand the inside shock absorbers are front right and rear right shockabsorbers. User mode modifiers 118 select the lookup table and/oralgorithm that defines the damping characteristics at each corner basedon above inputs.

If the throttle position is greater than the threshold Y at block 172,controller 20 operates the vehicle in a Squat Condition as illustratedat block 176. In the Squat Condition 176, controller 20 uses the modemodifiers for user mode 118, vehicle speed 120, throttle percentage 122,steering position 126, and steering rate 128 to control the dampingcharacteristics. Again, damping is increased base on increasing vehiclespeed. In addition, compression damping is increased on outside rearcorners based upon steering sensor, throttle sensor and vehicle speed.

In the Squat Condition 176, the controller 20 increases damping based onincreasing vehicle speed. Further, controller 20 increases compressiondamping on the outside rear corner shock based on inputs from thesteering sensor, throttle sensor, and vehicle speed. User mode modifiers118 select the lookup table and/or algorithm that defines the dampingcharacteristics at each corner based on above inputs.

FIG. 10 illustrates yet another embodiment of a damping control methodof the present disclosure including different sensor input optionscompared to the embodiments of FIGS. 8 and 9. In addition to throttlesensor 138, vehicle speed sensor 140, brake sensor 142, steeringposition sensor 158, and steering rate sensor 156, the embodiment ofFIG. 10 also uses a z-axis acceleration sensor 180 and an x-axisacceleration sensor 182 as inputs to the controller 20.

Controller 20 first determines whether acceleration from the z-axissensor 180 is less than a threshold C for a time greater than athreshold N as illustrated at block 184. If so, controller 20 determinesthat the vehicle is in a jump and controls the vehicle in a Jump/Pitchcondition as illustrated at block 186 where the suspension is allowed todrop out and the tires lose contact with the ground surface. In theJump/Pitch Condition 186, controller 20 uses condition modifiers for theuser input 118, the vehicle speed 120, and the z-axis accelerationsensor 134 to control the damping characteristics.

In the Jump/Pitch Condition 186, the controller 20 increases dampingbased on increasing vehicle speed. Further, controller 20 increasescompression damping on shocks at all four corners when an airborne eventis detected (and the duration of the airborne event) via negativevertical acceleration detected by the z-axis acceleration sensor 134.The controller 20 maintains the damping increase for a predeterminedduration after the jump event. If positive vertical acceleration isdetected by z-axis acceleration sensor 134 having a magnitude greaterthan a threshold value and for longer than a threshold duration (such aswhen contact with the ground is made after an airborne event), whereasgreater acceleration reduces the duration threshold required, rebounddamping may be increased to the rear and/or front shocks for an amountof time. User mode modifiers 118 select the lookup table and/oralgorithm that defines the damping characteristics at each corner basedon above inputs.

If an airborne event is not detected at block 184, controller 20determines whether an absolute value of the steering position is greaterthan a threshold X or an absolute value of the steering rate is greaterthan a threshold B at block 188. If not, controller 20 determineswhether the brakes are on and the x-axis acceleration is greater than athreshold value A at block 190. If so, controller 20 operates thevehicle in a Brake Condition as illustrated at block 192.

In the Brake Condition 192, condition modifiers for the user input 118,the vehicle speed 120, the x-axis accelerometer 130, and the y-axisaccelerometer 132 are used as inputs for the damping control. In theBrake Condition 192, the controller 20 increases damping based onincreasing vehicle speed. Further, controller 20 increases compressiondamping on an outside front corner shock based on inputs from steeringsensor 158, brake sensor 142, vehicle speed sensor 140, and/oracceleration sensor 180. User mode modifiers 118 select the lookup tableand/or algorithm that defines the damping characteristics at each cornerbased on above inputs.

If the determination at block 190 is negative, controller 20 determineswhether the throttle position is greater than a threshold Y asillustrated at block 194. If not, controller 20 operates the vehicle ina Ride Condition as illustrated at block 196. In the Ride Condition 196,controller 20 uses condition modifiers for the user-selected mode 118,the vehicle speed 120, a drive mode sensor such as four-wheel drivesensor 124, and the z-axis accelerometer 134 to control dampingcharacteristics. In the Ride Condition 196, the controller 20 increasesdamping based on the vehicle speed. User mode modifiers 118 select thelookup table and/or algorithm that defines the damping characteristicsat each corner based on above inputs.

If the throttle position is greater than threshold Y at block 194,controller 20 determines whether the vehicle speed is greater than athreshold Z as illustrated at block 198. If so, the controller 20operates the vehicle and the Ride Condition 196 as discussed above. Ifnot, the controller 20 operates the vehicle in a Squat Condition asillustrated at block 200. In the Squat Condition 200, controller 20 usescondition modifiers for the user mode 118, vehicle speed 120, throttlepercentage 122, and y-axis accelerometer 132 for damping control. In theSquat Condition 200, the controller 20 increases damping based on thevehicle speed. Further, the controller 20 increases compression dampingon the rear shocks and/or rebound damping on the front shocks based oninputs from throttle sensor 138, vehicle speed sensor 140, and/oracceleration sensor 180. Additional adjustments are made based on timeduration and longitudinal acceleration. User mode modifiers 118 selectthe lookup table and/or algorithm that defines the dampingcharacteristics at each corner based on above inputs.

If the absolute value of the steering position is greater than thethreshold X or the absolute value of the steering rate is greater thanthe threshold B at block 188, then controller 20 determines whether thebrakes are on and whether the x-axis acceleration is greater than athreshold A as illustrated at block 202. If so, controller 20 operatesthe vehicle in a Brake Condition as illustrated at block 204. In theBrake Condition 204, controller 20 uses condition modifiers for the usermode 118, vehicle speed 120, steering position 126, x-axis acceleration130, and y-axis acceleration 132 to adjust the damping controlcharacteristics of the electrically adjustable shocks. In the BrakeCondition 204, the controller 20 increases damping based on increasingvehicle speed. Further, controller 20 increases compression damping onan outside front corner shock based on inputs from steeling sensor 158,brake sensor 142, vehicle speed sensor 140, and/or acceleration sensor180. User mode modifiers 118 select the lookup table and/or algorithmthat defines the damping characteristics at each corner based on aboveinputs.

If a negative determination is made at block 202, controller 20determines whether the throttle position is greater than a threshold Yas illustrated at block 206. If not, controller 20 operates the vehiclein a Roll/Cornering Condition as illustrated at block 208. In theRoll/Cornering Condition 208, controller 20 uses condition modifiers forthe user mode 118, the steering position 126, the steering rate 128, they-axis acceleration 132, and the yaw rate 136 to control the dampingcharacteristics of the adjustable shocks. In the Roll/CorneringCondition 208, the controller 20 increases damping based on increasingvehicle speed. Further, controller 20 increases compression damping onthe outside corner shocks and/or rebound damping on the inside cornershocks when a turn event is detected via steering sensor 156 andaccelerometer 182. User mode modifiers 118 select the lookup tableand/or algorithm that defines the damping characteristics at each cornerbased on above inputs.

If the throttle position is greater than the threshold Y at block 206,controller 20 operates the vehicle in a Squat Condition as illustratedat block 210. In the Squat Condition 210, controller 20 uses conditionmodifiers for the user mode 118, the vehicle speed 120, the throttlepercentage 122, steering position 126, the steering rate 128, and they-axis acceleration 132 to control the damping characteristics of theadjustable shocks. In the Squat Condition 210, the controller 20increases damping based on the vehicle speed. Further, the controller 20increases compression damping on the outside rear corner shock based oninputs from throttle sensor 138, vehicle speed sensor 140, and/oracceleration sensors 180 or 182. User mode modifiers 118 select thelookup table and/or algorithm that defines the damping characteristicsat each corner based on above inputs.

Another embodiment of the present disclosure is illustrated in FIGS.11-13. As part of the damping control system, a stabilizer bar linkage220 is selectively locked or unlocked. The linkage 220 includes amovable piston 222 located within a cylinder 224. An end 226 of piston222 as illustratively coupled to a stabilizer bar of the vehicle. An end228 of cylinder 224 as illustratively coupled to a suspension arm orcomponent of the vehicle. It is understood that this connection could bereversed.

A locking mechanism 230 includes a movable solenoid 232 which is biasedby a spring 234 in the direction of arrow 236. The controller 20selectively energizes the solenoid 232 to retract the removable solenoid232 in the direction of arrow 238 from an extended position shown inFIGS. 11 and 12 to a retracted position shown in FIG. 13. In theretracted position, the end of solenoid 232 disengages a window 240 ofmovable piston 232 to permit free movement between the piston 222 andthe cylinder 224. If the solenoid 232 is in the extended position shownin FIGS. 11 and 12 engaged with window 240, the piston 222 is lockedrelative to the cylinder 224.

When the linkage 220 is unlocked, the telescoping movement of the piston222 and cylinder 224 removes the function of the stabilizer bar whilethe solenoid 232 is disengaged as shown in FIG. 13. When the controller20 removes the signal from the solenoid 232, the solenoid piston 232moves into the window 240 to lock the piston 222 relative to thecylinder 220. The solenoid 232 also enters the lock position if power islost due to the spring 234. In other words, the solenoid 232 fails inthe locked position. The vehicle is not required to be level in orderfor the solenoid 232 to lock the piston 222.

Unlocking the stabilizer bar 220 provides articulation benefits for thesuspension system during slow speed operation. Therefore, the stabilizerbar 220 is unlocked in certain low speed conditions. For higher speeds,the stabilizer bar 220 is locked. The controller 20 may also useelectronic throttle control (ETC) to limit vehicle speed to apredetermined maximum speed when stabilizer bar 220 is unlocked.

While embodiments of the present disclosure have been described ashaving exemplary designs, the present invention may be further modifiedwithin the spirit and scope of this disclosure. This application istherefore intended to cover any variations, uses, or adaptations of thedisclosure using its general principles. Further, this application isintended to cover such departures from the present disclosure as comewithin known or customary practice in the art to which this inventionpertains.

1. A damping control method for a vehicle having a suspension locatedbetween a plurality of ground engaging members and a vehicle frame, acontroller, a plurality of vehicle condition sensors, and a userinterface, the suspension including a plurality of adjustable shockabsorbers including a front right shock absorber, a front left shockabsorber, and at least one rear shock absorber, the damping controlmethod comprising: receiving with the controller a user input from theuser interface to provide a user selected mode of damping operation forthe plurality of adjustable shock absorbers during operation of thevehicle; receiving with the controller a plurality of inputs from theplurality of vehicle condition sensors including a z-axis accelerationsensor; determining with the controller when the vehicle is in anairborne event, the airborne event being determined when the input fromthe z-axis acceleration sensor indicates z-acceleration of less than afirst threshold that is sustained for a time greater than a secondthreshold to identify the airborne event; operating the damping controlaccording to an airborne condition when the airborne event isdetermined, wherein in the airborne condition the controller definesdamping characteristics of the plurality of adjustable shock absorbersbased on condition modifiers including the user selected mode and z-axisacceleration; and operating the damping control according to theairborne condition, wherein in the airborne condition the controllerincreases compression damping as a function of detected duration of theairborne event.
 2. The method of claim 1, wherein in the airbornecondition the controller increases compression damping on the frontright shock absorber, front left shock absorber, and at least one rearshock absorber.
 3. The method of claim 1, wherein the controllermaintains the damping increase of the airborne condition for apredetermined duration after conclusion of the airborne event givingrise to the airborne condition.
 4. The method of claim 1, furthercomprising: detecting positive vertical acceleration via the input fromthe z-axis acceleration sensor; determining with the controller when thevehicle is in a landing condition, the landing condition beingdetermined when the input from the z-axis acceleration sensor indicatesz-acceleration of greater than a third threshold that is sustained for atime greater than a fourth threshold; operating the damping controlaccording to the landing condition when a landing condition isdetermined, wherein in the landing condition the controller definesdamping characteristics of the plurality of adjustable shock absorbersbased on condition modifiers including the user selected mode and z-axisacceleration; and operating the damping control according to the landingcondition, wherein in the landing condition the controller increasesrebound damping.
 5. The method of claim 4, wherein the fourth thresholdis a dynamic threshold that is inversely correlated to the magnitude ofthe determined positive z-axis acceleration.
 6. The method of claim 1,wherein the z-axis acceleration sensor is coupled to the vehicle frame.7. The method of claim 1, further including: determining with thecontroller when the vehicle is not in the airborne event; anddetermining when the vehicle experiences at least one of: 1) an absolutevalue of a steering position is greater than a fifth threshold; and 2)an absolute value of a steering rate is greater than a sixth threshold.8. The method of claim 7, further including operating in a brakecondition upon: determining that the vehicle is not experiencing atleast one of: 1) an absolute value of a steering position is greaterthan a fifth threshold; and 2) an absolute value of a steering rate isgreater than a sixth threshold; and determining when the brakes areactivated and x-axis acceleration is greater than a seventh threshold.9. A vehicle having: a frame; a suspension located between a pluralityof ground engaging members and the frame, the suspension including aplurality of adjustable shock absorbers including a front right shockabsorber, a front left shock absorber, and at least one rear shockabsorber a plurality of vehicle condition sensors, a user interface, acontroller operable to control operation of the suspension, thecontroller including instructions thereon that when interpreted by thecontroller cause the controller to: receive a user input from the userinterface to provide a user selected mode of damping operation for theplurality of adjustable shock absorbers during operation of the vehicle;receive a plurality of inputs from the plurality of vehicle conditionsensors including a z-axis acceleration sensor; determine when thevehicle is in an airborne event, the airborne event being determinedwhen the input from the z-axis acceleration sensor indicatesz-acceleration of less than a first threshold that is sustained for atime greater than a second threshold; operate the suspension accordingto an airborne condition when the airborne event is determined, whereinin the airborne condition the controller defines damping characteristicsof the plurality of adjustable shock absorbers based on conditionmodifiers including the user selected mode and z-axis acceleration; andoperate the damping control according to the airborne condition, whereinin the airborne condition the controller increases compression dampingas a function of detected duration of the airborne event.
 10. Thevehicle of claim 9, wherein in the airborne condition the controllerincreases compression damping on the front right shock absorber, frontleft shock absorber, and at least one rear shock absorber.
 11. Thevehicle of claim 9, wherein the instructions further cause thecontroller to maintain the damping increase of the airborne conditionfor a predetermined duration after conclusion of the airborne eventgiving rise to the airborne condition.
 12. The vehicle of claim 9,wherein the instructions further cause the controller to: detectpositive vertical acceleration via the input from the z-axisacceleration sensor; determine when the vehicle is in a landingcondition, the landing condition being determined when the input fromthe z-axis acceleration sensor indicates z-acceleration of greater thana third threshold that is sustained for a time greater than a fourththreshold; operate the damping control according to the landingcondition when a landing condition is determined, wherein in the landingcondition the controller defines damping characteristics of theplurality of adjustable shock absorbers based on condition modifiersincluding the user selected mode and z-axis acceleration; and operatethe damping control according to the landing condition, wherein in thelanding condition the controller increases rebound damping.
 13. Thevehicle of claim 12, wherein the fourth threshold is a dynamic thresholdthat is inversely correlated to the magnitude of the determined positivez-axis acceleration.
 14. The vehicle of claim 9, wherein the z-axisacceleration sensor is coupled to the vehicle frame.
 15. The vehicle ofclaim 9, wherein the instructions further cause the controller to:determine with the controller when the vehicle is not in the airborneevent; and determine when the vehicle experiences at least one of: 1) anabsolute value of a steering position is greater than a fifth threshold;and 2) an absolute value of a steering rate is greater than a sixththreshold.
 16. The vehicle of claim 9, wherein the instructions furthercause the controller to operate in a brake condition upon: determiningthat the vehicle is not experiencing at least one of: 1) an absolutevalue of a steering position is greater than a fifth threshold; and 2)an absolute value of a steering rate is greater than a sixth threshold;and determining when the brakes are activated and x-axis acceleration isgreater than a seventh threshold.
 17. A vehicle having: a frame; asuspension located between a plurality of ground engaging members andthe frame, the suspension including a plurality of adjustable shockabsorbers including a front right shock absorber, a front left shockabsorber, and at least one rear shock absorber a plurality of vehiclecondition sensors, a user interface, a controller operable to controloperation of the suspension, the controller including instructionsthereon that when interpreted by the controller cause the controller to:receive a user input from the user interface to provide a user selectedmode of damping operation for the plurality of adjustable shockabsorbers during operation of the vehicle; receive a plurality of inputsfrom the plurality of vehicle condition sensors including a z-axisacceleration sensor; detect positive vertical acceleration via the inputfrom the z-axis acceleration sensor; determine when the vehicle is in alanding condition, the landing condition being determined when the inputfrom the z-axis acceleration sensor indicates z-acceleration of greaterthan a first threshold that is sustained for a time greater than asecond threshold; operate the damping control according to the landingcondition when a landing condition is determined, wherein in the landingcondition the controller defines damping characteristics of theplurality of adjustable shock absorbers based on condition modifiersincluding the user selected mode and z-axis acceleration; and operatethe damping control according to the landing condition, wherein in thelanding condition the controller increases rebound damping.
 18. Thevehicle of claim 17, wherein the second threshold is a dynamic thresholdthat is inversely correlated to the magnitude of the determined positivez-axis acceleration.
 19. The vehicle of claim 17, wherein in the landingcondition the controller increases rebound damping on the front rightshock absorber, front left shock absorber, and at least one rear shockabsorber.
 20. The vehicle of claim 17, wherein the z-axis accelerationsensor is mounted on the vehicle frame.